Children’s brains need time to develop crucial listening skills
[Development of binaural temporal fine structure sensitivity in children]
The ability to hear clearly and understand speech in a noisy environment, such as a typical classroom, is much easier when you can use both ears. Using both ears (binaural) allows our brain to know which direction a sound is coming from. Knowing where a sound is coming from makes it easier to do things like focus on one person talking among a group of people speaking. This has been called “the cocktail party effect”. Children are generally worse at being able to hear speech clearly when there is background noise, such as other voices. The ability to understand speech in noise improves with age and research has shown it is only fully developed at 10 – 12 years old. The reason for this has not been fully understood. Binaural differences in loudness and time of arrival of sound all adds to the way the brain works out where sound is coming from. One aspect that has not been investigated in children before is the frequency range over which the brain is able to combine binaural sounds to achieve a sense of location. Young normal hearing adults can detect a difference in the phase, or the binaural ‘Temporal Fine Structure’, of sound across the ears up to around 1400 Hz. Our investigations with children (aged 5.5 to 9.3 years) revealed that even though they can hear the sounds, the frequency range over which children can combine the binaural Temporal Fine Structure, is significantly smaller and lower. The upper frequency limit for binaural temporal fine structure sensitivity increased with age, and our results suggests that adult like sensitivity is achieved on average at 10.2 years old.
One significance of these findings relates to the environmental characteristics of spaces designed for teaching and learning. It is obviously important that a teacher can be heard clearly by their pupils. Clarity can be improved by design of the classroom to have low background noise and reverberation with a particular focus on frequencies below 1400 Hz.
Find link to paper here: https://doi.org/10.1121/10.0006665